Wireless technologies for communication between devices are increasing in order to enable V2X wireless communication systems. V2X uses vehicular wireless communication systems to exchange information between vehicles and other entities, including other vehicles, pedestrians and roadside devices. V2X may be used to improve vehicle safety and to eliminate the excessive societal and property damage cost of traffic collisions. In addition, V2X may help in avoiding traffic congestion and finding better driving routes by processing real-time traffic data. This in turn saves time, improves fuel efficiency, and has significant economic and environmental advantages. V2X may include different classes of relevant services such as vehicle-to-infrastructure (V2I), vehicle-to-vehicle (V2V), vehicle-to-pedestrian (V2P), vehicle-to-device (V2D) and vehicle-to-grid (V2G). In all services, there are significant safety, mobility and environmental benefits if a vehicle is able to communicate with its surroundings.
V2X systems may use orthogonal frequency-division multiplexing (OFDM) and single-carrier frequency-division multiple access (SC-FDMA) which are also used in current communication standards including long term evolution (LTE) and wireless fidelity (Wi-Fi). For robust symbol demodulation performance, accurate estimation and compensation of the time offset (TO) and frequency offset (FO) of received signals are essential to such systems. TO may result in inter-symbol interference (ISI) and FO may result in inter-carrier interference (ICI).
One of the challenges in V2X wireless communication systems is accurate TO and FO estimation in a high speed propagation environment. In such a high speed propagation environment, the transmitter and/or the receiver in a vehicle may be moving at the time of communication in contrast to legacy LTE or Wi-Fi communication systems, where the downlink transmitter (such as a base station or access point) is stationary.